Overview
ISO/IEC 7942-2:1997 is an international standard developed by ISO and IEC focusing on computer graphics and image processing within the context of the Graphical Kernel System (GKS). Specifically, this standard defines the NDC (Normalized Device Coordinate) metafile format. The NDC metafile is a structured, device-independent file format designed for the storage and retrieval of graphical picture information in a way that enables interoperability across different computer architectures and graphics devices.
The NDC metafile standard serves as an extension to established computer graphics metafile formats, supporting a reliable means to encode, exchange, and reproduce graphical content using the GKS specifications.
Key Topics
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NDC Metafile Structure: Outlines the logical organization, starting with a header, a set of descriptors, independent picture elements, and employing various delimiters for clear segmentation.
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Encoding Methods: Describes abstract, binary, and clear text encoding schemes for the GKS-94 NDC metafile elements, enabling interoperability in various computing contexts.
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Metafile Elements & Attributes: Covers a wide set of elements including graphical primitives (such as polylines, NURBs, polygons), attribute elements (such as color, transformations, scissor sets), control elements, and application structure elements.
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Device Independence: Encodings are carefully specified to maintain consistency and accuracy across diverse system architectures and output devices.
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Extension Mechanism: Builds on the CGM Version 4 (Computer Graphics Metafile) standard, introducing extensions and new elements to support the broader capabilities of GKS-94 output primitives and attributes.
Applications
Implementing ISO/IEC 7942-2:1997 is essential in environments where standardized graphical data interchange is a requirement. Typical use cases include:
- CAD and Engineering Systems: Enables the reliable archival, retrieval, and exchange of complex graphics and drawings between heterogeneous systems.
- Scientific and Technical Visualization: Supports the storage and distribution of rendered images and diagrams which must remain platform-independent.
- Cross-Platform Graphics Interchange: Facilitates communication across applications and devices employing different graphics hardware and operating systems.
- Long-Term Data Preservation: The standardized metafile format ensures that graphical data can be reconstructed accurately in the future, regardless of changes in device technology.
Organizations and software solutions that rely on precise, repeatable rendering of graphical images can benefit from complying with this standard, which guarantees a consistent approach to encoding and processing graphical information.
Related Standards
When working with ISO/IEC 7942-2:1997 NDC metafiles, the following international standards are also relevant:
- ISO/IEC 7942-1:1994: Information technology - Computer graphics and image processing - Graphical Kernel System (GKS) - Part 1: Functional description.
- ISO/IEC 8632:1992/Amd.2:1995: Information technology - Computer graphics - Metafile for the storage and transfer of picture description information (CGM), all parts.
- Other parts of ISO/IEC 7942:
- Part 3: Audit trail
- Part 4: Picture part archive
These references provide foundational definitions, additional metafile formats, and comprehensive guidance for the implementation of GKS-compliant graphical solutions. Adherence to these standards ensures robust, interoperable, and future-proof handling of computer graphics data.
Keywords: ISO/IEC 7942-2, NDC metafile, Graphical Kernel System, GKS, computer graphics standard, CGM, device-independent graphics, graphical data exchange, image processing, international standard, encoding methods.
Open preview (PDF)Information technology — Computer graphics and image processing — Graphical Kernel System (GKS) — Part 2: NDC metafile
